CN110114280B

CN110114280B - Perfusion closure

Info

Publication number: CN110114280B
Application number: CN201780078961.6A
Authority: CN
Inventors: G·科老特科拉莫
Original assignee: Bericap Holding GmbH
Current assignee: Bericap Holding GmbH
Priority date: 2016-12-20
Filing date: 2017-12-13
Publication date: 2021-04-13
Anticipated expiration: 2037-12-13
Also published as: EP3558840B1; US11174078B2; PE20191216A1; US20190329938A1; ES2927198T3; EP3558840A1; CN110114280A; PL3558840T3; DE102016124947A1; WO2018114513A1; BR112019011313A2

Abstract

The invention relates to a pouring closure for a liquid container having a pouring opening (10) which can be sealingly fixed to the container neck and whose cross section is closed before use by a membrane (1), wherein a portion (1') of the membrane (1) extends transversely on the membrane (1) and is substantially pear-shaped in plan view, which portion is connected to the remaining portion via a readily tearable weakening line (2) and can be separated from the membrane (1) such that after separation it releases an opening (5) in the membrane (1), which opening corresponds to a pear shape in plan view, such that liquid can be poured selectively from a relatively narrower section (6) or from a relatively wider section (7) of the pear-shaped opening (5) depending on the orientation of the container when the container is tilted. In order to provide a pouring closure for a liquid container of the type mentioned at the outset, in which, on the one hand, a pouring opening can be formed in a very controlled and well-defined manner by tearing off a film section, and, on the other hand, metered pouring of the liquid is further facilitated, it is proposed according to the invention that the film (1) has, on its inner surface, a web (8) which runs parallel to the line of weakness (2) at a relatively close distance and outside the tear-off section, the web extending inwardly away from the film surface and substantially transversely thereto, and on both sides of the narrower section (6) of the tear-off portion (1') or on both sides of the opening (5) and along at least a part of the transition region (9) between the narrower section and the wider section.

Description

Perfusion closure

Technical Field

The present invention relates to a pouring closure for a liquid container having a pouring opening which can be sealingly secured to the container neck and whose cross-section is closed before use by a membrane, wherein a portion of the membrane extends transversely away from (over) the membrane and is substantially pear-shaped in plan view, which portion is connected via an easily tearable weakening line to a remaining portion which portion can be separated from the membrane and release (uncover) the membrane opening, which membrane opening corresponds to a pear-shape in plan view, so that liquid can be selectively poured out of a relatively narrower section of the pear-shaped opening or out of a relatively wider section of the pear-shaped opening upon tilting of the container, depending on the orientation of the container.

Background

The term "pear-shaped" defines here consecutive sections of the surface, wherein the sections are connected to each other, and wherein smaller sections tend to have a narrower elongated shape, while wider sections tend to have a rounded shape closer to a substantially circular shape.

This definition applies, for example, to the profile of the plough, which comprises a relatively narrow, more or less conical or slightly bell-shaped section, which via a concave curvature changes to a more spherical end. However, the actual shape, in particular the width and shape of the narrower sections relative to the wider sections, may differ to a large extent from a real pear and employ, for example, a mushroom or a water tower profile (see example embodiments). The narrower section may in particular also be delimited by two parallel sides and may be 5 to 20 times narrower over most of its length than the maximum width of the wider section. All of these shapes come together under the term "pear shape", even though a real pear would not have such a contour.

Finally, with the same specific shape of the opening as is known in the art, it is crucial that the flow rate is substantially more restricted when the liquid is poured out only through a narrower section, and that the amount of liquid can thus be metered more easily than when poured out through a wider section. To more accurately meter the amount of liquid, the user rotates the container so that when the container with the pouring opening is tilted, the narrower section of the opening in the membrane is at the bottom, so that liquid only comes out of this narrower section, as long as the container is not tilted too much so that the liquid level will also reach the area of the wider opening. The inclined position in which the narrower section with the opening is turned downwards is referred to herein as the "metering position".

If, on the other hand, a relatively large quantity of liquid is to be poured out of the container or the container is to be completely emptied, the container can be rotated such that, when it is tilted, the wide opening is situated at the bottom, resulting in a large quantity of liquid flowing out of its cross section, which is substantially larger than the cross section of the narrow opening and, in addition, is substantially circular, which results in a reduced flow resistance also in the case of the same cross section compared to a longer, narrow cross-sectional shape.

However, prior to use, the pear-shaped opening is closed by a membrane, and the exact shape of the opening is defined here by the course of a line of weakness on an otherwise disc-shaped membrane which completely closes the generally cylindrical cross-section of the pouring opening prior to use.

Naturally, the pouring opening may also have a cross-sectional shape other than circular, so that the shape of the membrane needs to be adapted correspondingly. It is finally only essential for the invention that the mentioned "pear-shape" of the pouring opening, which achieves the above-mentioned desired pouring properties, is obtained after a part of the membrane has been torn open, wherein, at least outside the narrower section of the opening formed, a part of the original membrane still limits the free cross-section of the pouring opening.

A corresponding closure is known from FR 2963779, in which a film extending transversely over the pouring cross-section has a large opening and a small opening, which are connected to one another via a narrow point and are released by tearing apart separable parts of the film along a weakening line. Here, also, connection tabs are provided on the inner surface of the membrane, next to the line of weakness, which extend inwardly away from the membrane surface and around the small opening and from the small opening up to the sides of the large opening along a narrow point between the small and large openings. The web has its maximum height in the region of the small opening and ensures an inflow of air and prevents the liquid from flowing out through the small opening, so that glugging is prevented or the liquid intermittently leaves the closure opening when the liquid is poured out. In this embodiment, accurate metering of the liquid by pouring through only a small opening is almost impossible.

Pouring closures of the above-mentioned type (and therefore also pouring closures according to the invention) are often used in containers for edible oils, which sometimes have to be metered more precisely depending on the application.

In the case of pouring closures of this type, to the extent that they are known per se, it has however proved problematic to design the narrower and wider sections of the pouring opening such that, when the container is tilted, the liquid leaves virtually always only through the desired narrower or wider region and also forms an easily handled and uniformly exiting liquid (jet) stream in the process.

Another problem with this form of pouring opening created by separating a portion of the membrane is the stability of the line of weakness and the stability of the area adjacent to the line of weakness. In principle, the membrane is a one-piece disk, the outer contour of which is generally cylindrical and in any case matches the inner contour of the pouring opening. The weakening lines are introduced during injection moulding or alternatively by engraving or pressing corresponding contours into the surface on one side of the disc, for example into its outer surface. Usually, a pull-out aid, in particular a pull ring, is attached at the free end of the wider section of the film portion to be separated, so that for the use of the closure by a user, the wider section is first pulled out of the plane of the film by means of the pull ring, while the film tears along the weakening line.

The respective ends of the narrower and wider sections facing away from each other (both for the separable part of the membrane and for the opening formed) are referred to herein as the "free ends" of the narrower and wider sections, respectively. The terms "narrow" and "wide" are not absolute, but are understood to be relative.

However, in particular in the case of a change in the course of the weakening line or in the region of the narrower sections, it can happen that the film does not tear precisely along the weakening line, but instead the film material close to the weakening line begins to tear, wherein this tear, once introduced into the film material, continues in a completely uncontrolled manner upon further pulling of the tab, so that a more or less undefined opening is formed, or additional parts of the film also tear and partly also project into the resulting opening, so that the opening is again partly obstructed. This results in uncontrolled liquid pouring characteristics when the container is tilted, even when the user tries to orient the opening which is now produced but which is irregularly shaped and different from what is desired, so that the amount of liquid which leaves can be metered out controlled and as accurately as possible.

It has furthermore been found that metering of the liquid in the case of relatively full containers is still difficult, since the liquid level quickly reaches the transition to the wider region, often when the container is only slightly tilted and the narrow opening is turned downwards or in the direction of the tilt, and then when the upper end of the narrow section is only marginally exceeded, a significantly greater amount of liquid flows out through the abruptly widened opening. This is particularly applicable to high viscosity liquids, such as edible oils, which tend to have uncontrolled venting characteristics (gurgling to pour or intermittently to exit).

For this purpose, corresponding so-called "vent closures" have also been developed in the prior art, which reduce the outlet cross-section and have a series of smaller slits adjacent to the central filling cross-section, through which air can better flow into the container.

Since such venting slits or openings with star-shaped extensions are usually located below the region of the pouring opening closed by the membrane, it is also possible to additionally combine these venting elements with the subject matter of the present invention.

Finally, already superficial in the case of such conventional closures, even if the container is merely tilted enough for the liquid to exit only through the narrower section, the exiting liquid (jet) stream is not uniform and smooth, but is instead partially split (into multiple portions), with varying cross-sections and/or undulations.

Disclosure of Invention

As opposed to the prior art mentioned above, the object of the present invention is therefore to propose a pouring closure for a liquid container of the type mentioned at the outset, in which on the one hand the pouring opening can be produced in a very controlled and well-defined manner by tearing off the film section and on the other hand the metered pouring out of the liquid is further facilitated.

This task is achieved in that the membrane has, on its inner surface, a connecting web (Steg) which, outside the tear-open section of the membrane, at a short distance next to the weakening line, extends inwardly away from the membrane surface, i.e. in the direction of the interior of the container, and runs (extends) on both sides of the tear-open portion of the membrane or on both sides of the corresponding opening and at least along at least a part of the transition region between the narrower and wider sections, wherein the connecting web height increases from their first end, which is close to the narrower section, remote from the wider section, as it approaches the transition region.

Due to their shape and structure, the webs enable the liquid to leave through the narrower regions when pouring out with the narrower regions turned downwards, as the webs become higher towards the transition regions, and enable the liquid to leave through the narrower regions with an inclination angle at which the webs still shield the wider regions from the exiting liquid.

The webs do not already have their maximum height near the lower end of the narrow opening, because the web height increases from the beginning of the web, close to the first end of the narrower section (which is remote from the wider section), as it approaches the transition region, and preferably at least doubles up to the maximum web height.

The web height can thus be, for example, 2mm near the lower end of the narrow opening and, for example, 5mm near the transition region, wherein the web height can then be reduced again in its further course if the web also extends further into the region of the wider section, significantly. The web preferably ends along the wider area but at a distance in front of the outer edge of the membrane, while the wide opening clearly (significantly) approaches the outer edge of the membrane or the inner wall of the pouring opening and is for example less than 2mm, preferably less than 1mm, at the end of the wide opening opposite the narrower section. In this region, only residues of the film remain, which is caused by the weakening line not ending flush with the film in this region.

If the narrow opening then points downwards when the container is tilted, wherein the liquid level gradually rises from the lower edge to the upper edge of the narrow opening as the angle of tilt becomes larger, liquid will initially only flow out of the narrow section of the opening, and in the case of a greater tilt, when the liquid level reaches the end of the narrow section, the liquid is prevented by the web from flowing past the narrow opening and directly into the adjacent region of the wider opening and thus suddenly leaves the pouring opening in a greater amount.

The webs running along the transition region and as far as or into the wider region conversely deflect or pull the liquid outwards and, in the case of still larger angles of inclination, would only allow the liquid to flow out over their upper edges and then over the wider sections.

Due to this flow deflection and blockage, these webs are also referred to as "deflectors".

The connecting piece has, for example, the shape of a strip with a substantially rectangular cross section which may vary along its extension along the weakening line, mainly in a direction perpendicular to the surface of the film. Specifically, the larger cross-sectional dimension of the tab extends (travels) perpendicular to the inner surface of the film.

The connecting webs running parallel to the transition region and the adjacent portion of the narrower section first form a kind of edge reinforcement of the weakening line or of the opening formed, where in the case of conventional closures of this type the film often starts tearing in an uncontrolled manner outside the region provided for the opening. The connecting tab prevents the film from starting to tear along the weakening line, in the direction of the portion located outside the opening.

Furthermore, in an embodiment, the narrower tear-open portion of the film may also be reinforced by a further web which extends along the narrower section and approximately in its centre and is referred to hereinafter for convenience of distinction as a "rib". Since the weakening line has to extend in narrower sections at a short distance therefrom on both sides of the rib, the rib is also at a short distance from the weakening line, since the weakening line here only delimits the opening or a correspondingly narrower section of the tear-off portion of the film.

This central rib reinforces the tear-open section close to the weakening line and reinforces the narrower tear-open section as a whole and in this way avoids that the film material starts tearing on one side of the narrower section when the tear-open portion is torn open. In the process, the narrower section may tear before the line of weakness separates until the free end of the narrower section.

Thus, the connecting piece and the central rib ensure: the film starts to tear and the torn film portion tears along the entire circumference of the opening and in particular in the narrower part of the opening precisely along the predefined weakening line. The narrow opening thus produced is thus reliably and precisely defined, wherein this is also true for the wider part of the opening, in which, however, small deviations from the precise contour of the weakening line are not so important, since a precise metering of the wide opening need not be achieved.

As regards the distance from the weakening line, as well as the connecting tab, it applies basically to a reinforcing rib, wherein the distance is ultimately determined by the width of the separable portion and the width of the rib, and wherein, in the case of a narrower section, which is intended to have a width of 10mm or more, the reinforcing rib can also be provided in the form of two parallel ribs along the weakening line on the separable portion.

However, one difference between the stiffening ribs reinforcing the narrower portions of the membrane and the tabs outside the narrower sections is primarily in the height of the tabs or stiffening ribs. Although, for example, a double or at most three times the wall thickness of the membrane is sufficient for the pure reinforcing function, connecting webs on the inner surface of the membrane, along the narrower sections of the separable parts and in the transition region or along the formed openings have a further function, which influence the filling properties of the liquid. For this reason, the maximum height of the connecting web, measured perpendicular to the membrane surface, is between 2 and 10mm, or more generally greater than 10% and up to 50% of the inner diameter of the pouring openings for pouring closures with different dimensions, wherein in the case of non-cylindrical pouring openings the average value of the inner diameter can be used here as a reference. The webs may have a zero value for their minimum height at their outer ends, wherein it is preferred for the webs, however, to start close to the free end of the narrower section already at or immediately adjacent to the wall of the pouring opening (for example, at most 2mm distance, preferably at most 1mm distance) and to have an initial height of at least 1mm, preferably at least 2 mm.

The maximum height of the connecting web is preferably located near the transition from the narrower section to the wider section of the opening or near the separable portion of the membrane. The pear-shaped transition region is defined here, for example, by a concave section of the outer contour. Although the narrower section is substantially convexly (convexly) curved at its ends and is otherwise defined by, for example, a straight and in particular parallel contour line, the transition to the wider region must occur at some point where it is necessary to have a concave contour.

The transition region is also defined and defined by the concave section, as long as the concave contour is clearly identifiable. In the case of opening profiles which do not clearly identify a concave transition region and which in particular do not narrow to a region which is below 20% of the diameter of the pouring opening (measured between the wider and narrower sections opposite one another), the transition region is defined by a region whose boundary lies between 45% and 55% of the distance between the free ends of the narrower and wider sections. In any case, the opening widens in the region of the transition section in a concave manner or in a manner diverging on both sides, and it precisely in this region causes the connecting pieces to have their maximum height, which may be, for example, 5mm or 6mm in the case of a pouring opening having a diameter of 20mm, for example.

In the case of webs along narrower sections, it is not absolutely necessary in practice for them to be close to the free end of the section and therefore already start at or close to the edge of the film; it has however been shown that the flow characteristics of the liquid, in particular edible oil, become particularly uniform (homogeneous) in almost all cases, in particular also in the case of small tilting angles of the container, if the web starts at a distance of less than 3mm, preferably less than 2mm, from the edge of the outer film, wherein the free end of the narrower section is also at a distance of at most 1mm from the edge of the film.

The distance of the connecting flaps from the weakening line along the narrower sections and preferably also along the transition regions is at most 10% of the film diameter, in particular at most 3mm and preferably at most 2 mm.

The pear-shaped opening, i.e. the entire pouring opening comprising the narrower and wider sections, extends with its ends facing away from each other over substantially the entire diameter of the membrane and preferably also the geometric centre of the membrane, wherein a slight offset or displacement towards the membrane centre is not significant.

The narrower section extends from its first end of the wall located close to the pouring opening to the centre of the membrane, and preferably slightly beyond it, and is preferably defined by two parallel side edges at a clear distance from each other of from 1mm to 3 mm.

The wide opening has a maximum width which in one embodiment is at least one third, preferably more than half, of the membrane diameter, wherein the wide opening extends in the radial direction at least as far as the narrower section over slightly less than half of the membrane diameter. In any case, in some embodiments, the length and width of the narrower section and the length and width of the wider section are selected such that the cross-section of the narrower section is less than one third of the cross-section of the wider section. The cross-sectional area of the wider section is preferably at least one fifth relative to the total membrane surface area.

Expediently, one of the two free ends of the separable part of the membrane, thus the free end of the narrower section or the end of the wider section facing away therefrom, is provided with a pull-out aid, which is preferably formed as a pull ring.

Drawings

Further advantages, features and possible applications of the invention will become clear with reference to the following description of preferred embodiments and the associated drawings. Shown in the attached drawings:

figure 1 is a plan view of the pouring closure from the inside and below,

figure 2 is a side view of the closure member,

fig. 3 is a view from above of the closure according to fig. 1, wherein the tab has been omitted,

figure 4 is a cross-sectional view along line BB in figure 1,

figure 5 is a perspective view of the pouring closure from below,

figure 6 is a plan view of the closed membrane from below,

fig. 7 is a plan view of the opened film as viewed from below.

Detailed Description

In fig. 1 to 5 a closure 100 is visible which can be snapped onto a cylindrical neck of a container and has an outer closure housing 20 enclosing the container neck from the outside and an inner pouring opening 10, the lower section of which tightly engages the inner surface of the container neck. The transition between the lower section and the upper section 10' of the pouring opening 10 is closed by a membrane 1 extending over the cross section of the pouring opening 10. The closure also has a threaded attachment 30 around the upper section of the pouring opening 10 for closing by means of a screw cap (not shown).

In a plan view from above according to fig. 3, the membrane 1 is visible inside the pouring opening 10, the membrane 1 having a substantially pear-shaped, centrally located and detachable portion 1', which is bordered by a weakening line 2 shown in bold lines. The weakening line 2 is introduced (engraved or pressed in) from the outside to the surface of the film 1 and is therefore not visible in the view from below (fig. 1).

In the perspective view from below according to fig. 5, two curved connecting tabs 8 running on the inner surface of the film on the left and right can be seen, which substantially follow the course of the weakening line 2 without making it visible in fig. 5, and indeed, as can be seen in fig. 6, above all along the narrower section of the detachable portion 1', beyond the transition zone 9, and which extend into the lower half of the wider section of the tear-off portion 1' of the film 1.

The transition zone is defined here by a section of the weakening line between the narrower and wider sections of the detachable portion 1', characterized by a concave curvature of the weakening line, the weakening line having a substantially convex course in the remaining part.

Furthermore, also visible in fig. 5 is a central rib 11 extending diametrically on the inner surface of the membrane, which mainly serves to reinforce the narrower section of the detachable portion 1'. The height of the ribs 11 increases along the narrower section of the portion 1' towards the free end of this narrower section (fig. 4).

In the sectional view according to fig. 4, it can furthermore be seen that, in side view, the connecting web 8 has a relatively low connecting web height starting from a point close to the free end of the narrower section of the separable portion 1' of the film 1, which then rises approximately linearly to a maximum and decreases again towards the other end bent away from the plane of fig. 4. The maximum height of the connecting piece 8 is located in the region of the transition region 9 closest to the weakening line. The perspective illustration in fig. 5 shows the shape and course of the web 8 relatively well. In this region, the connecting tab also has a concave curvature in plan view, similar to the line of weakness 2.

The free end of the wider section of the separable portion 1' of the membrane is connected to the tab 12 so that when the tab 12 is pulled, initially the free end of the wider section of the separable portion 1' is separated and torn away from the membrane 1 along the line of weakness 2, and then when the tab 12 is pulled further, the connection between the separable portion 1' and the remainder of the membrane 1 splits along the line of weakness 2. Finally, beyond the transition zone 9, the narrower section of the separable portion 1 'is also known from the tension applied to the tab, so that the entire separable portion 1' of the film can then be separated along the line of weakness (see fig. 6) and removed.

In the transition zone 9 and along the narrower section, the central rib 11 and the connecting tabs 8, which form the reinforcement of the film material on both sides of the weakening line 2, ensure that: the film does not start tearing from either side of the weakening line 2, which results in the edges of the opening being formed then extending in an uncontrolled manner. The reinforcement by the connecting tab 8 and the rib 11 thus ensures that the detachable portion 1 'of the film 1 tears apart exactly along the predefined weakening line 2 also in the transition region 9 and in the narrower region, and then leaves an opening 5, the opening 5 exactly corresponding to the shape of the detachable portion 1' predefined by the weakening line.

The opening formed in this way is designated as a whole by 5, the narrower part of the opening 5 by 6 and the wider part of the opening 5 by 7 (see fig. 7).

The reinforcing rib 11 is removed together with the separable part 1' of the film so that finally the film 1 is left with said opening 5 and the tab 8, the tab 8 extending mainly along the narrower section 6 of the opening, along the transition area 9 and along the edge of the wide opening in the section adjacent to the transition area up to a distance before the periphery of the film.

With reference to fig. 7, it can also be seen that in the region of the narrow opening 6 and also in the transition region 9, the connecting piece 8 follows the edge or weakening line 2 of the narrow opening 6 parallel thereto at a relatively close distance. The ends of the webs 8 extending away from each other beyond the transition region can then be at increasingly greater distances from the wider sections 7 of the openings 5.

With reference to the perspective illustration of the connecting web 8 in fig. 5 and also taking into account the profile of the connecting web according to the illustration in fig. 4, it can be seen that after tilting of the container and pouring of the closure in the metering position, when the liquid flows against the inner surface of the membrane and simultaneously creates the opening 5, the liquid can initially flow to and through the corresponding narrow opening 6 only between the sides of the connecting web 8 extending in parallel.

As the liquid level rises due to an increasing angle of inclination, the web becomes higher and higher towards the transition region preventing liquid from flowing also laterally in the direction of and through the wider opening 7. It is hereby achieved that the inclination angle of the container can be varied over a wide range without the liquid overcoming the obstacle of the connecting piece 8. The liquid is deflected outwards by the web 8 into a region which, in the case of relatively large tilting angles, is situated only below the liquid level. The connecting piece is also referred to herein as a "deflector" for this reason. The liquid can then still leave through the entire cross section of the narrower region, without a significant additional amount of liquid also being able to flow out through the wider section 7 of the opening 5. In this way, it is ensured that, in contrast to closures which do not have such a web at all, the metering position allows a much greater range of angles of inclination, thus significantly contributing to the metering of the liquid.

If the closure or the container is rotated such that the wide opening 7 is located at the bottom (below the liquid level or in the region of the liquid level) when the container is tilted, the wide opening 7 is completely freely accessible for the liquid flowing to it, the webs 8 then represent a hardly important obstacle for the flow, since they can now deflect the flowing liquid inwards in the direction of the wide opening 7 in the opposite direction, wherein the narrow opening 6 then serves as a ventilation opening.

At the same time, the connecting web 8 also serves as a reinforcing element when the separable part 1' of the membrane is torn open, and thus ensures that a precisely defined, desired shape of the pouring opening with the

sections

6 and 7 is produced.

Reference numerals:

1 film

1' separable part

2 lines of weakness

5 opening (whole)

6 narrower part of opening

7 wider part of opening

8 connecting sheet

9 transition region

10 perfusion opening

11 Ribs

12 pull ring

20 closure shell

30 screw attachment

100 closure member.

Claims

1. Pouring closure for a liquid container with a pouring opening (10) which can be sealingly fixed to the container neck and whose cross-section is closed before use by a membrane (1), wherein a portion (1') of the membrane (1) extends transversely over the membrane (1) and is substantially pear-shaped in plan view, said portion being connected to the remaining portion via a readily tearable weakening line (2) and being separable from the membrane (1) such that after separation it releases an opening (5) in the membrane (1), which opening corresponds to a pear-shape in plan view, so that, depending on the orientation of the container when it is tilted, liquid can be poured selectively from a narrower section (6) or from a wider section (7) of the pear-shaped opening (5), wherein the membrane (1) has a connecting web (8) on its inner surface, the tab extends inwardly away from the film surface at a short distance beside the weakening line (2) and outside the tear-off section, and the tab extends on both sides of the narrower section (6) of the tear-off portion (1') or on both sides of the opening (5) and along at least a part of the transition region (9) between the narrower section and the wider section, and wherein the tab height increases from the beginning of the tab (8), close to its first end of the narrower section (6) remote from the wider section (7), as it approaches the transition region (9).

2. Pouring closure according to claim 1, wherein the maximum height of the connecting piece 8 measured perpendicular to the membrane surface is between 2 and 10mm, and in particular is more than 10% and up to 50% of the inner diameter of the pouring opening.

3. Pouring closure according to claim 1, wherein the web height is at least doubled up to a maximum web height as it approaches the transition region (9) from their first end of the narrower section (6) away from the wider section (7) where the web (8) starts.

4. Pouring closure according to claim 1, wherein the connecting web height is reduced from a maximum height by at least 50% in the transition area to the second end beside the wider section (7).

5. Pouring closure according to claim 1, wherein the minimum height of the connecting web (8) near the free end of the narrower section (6) of the opening is 1 mm.

6. Pouring closure according to claim 1, wherein the minimum height of the connecting web (8) near the free end of the narrower section (6) of the opening is 2 mm.

7. An irrigation closure according to claim 1 wherein said web extends beyond said transition region but terminates a distance before the outer edge of said membrane.

8. Pouring closure according to claim 1, wherein along the narrower section and also along the transition region (9) the connecting web is at a distance of at most 10% of the membrane diameter from the weakening line (2).

9. Pouring closure according to claim 1, wherein the distance of the connecting tab from the weakening line (2) along the narrower section and also along the transition region (9) is at most 3 mm.

10. Pouring closure according to claim 9, wherein along the narrower section and also along the transition region (9) the connecting tab is at a distance of at most 2mm from the weakening line (2).

11. Pouring closure according to claim 1, wherein the narrower section of the tear-off portion (1') of the membrane (1) has a reinforcing rib (11) extending parallel to both edges of the narrower section.

12. Pouring closure according to claim 11, wherein the reinforcing ribs extend on the inner surface of the membrane (1).

13. Pouring closure according to claim 1, wherein the pear-shaped opening (5) extends with its free ends, facing away from each other, of the narrower section (6) and the wider section (7) over substantially the entire diameter of the membrane.

14. Pouring closure according to claim 13, wherein the pear-shaped opening (5) also comprises the geometric centre of the membrane.

15. An irrigation closure according to claim 1 wherein the narrower section has a maximum width less than one quarter of the membrane diameter and the wider section has a maximum width greater than one third of the membrane diameter.

16. An irrigation closure according to claim 15 wherein said narrower section has a maximum width less than 15% of the membrane diameter and said wider section has a maximum width greater than half the membrane diameter.

17. Pouring closure according to claim 1, wherein the edge of the pear-shaped opening (5) has a substantially convex shape or extends in a straight line in the narrower section (6) and the wider section (7), wherein the transition area (9) between the narrower section and the wider section is defined by the concave course it has.

18. A pouring closure according to claim 1, wherein said transition area is defined by sections located between 45% and 55% of the distance between the free ends of the narrower and wider sections opposite each other.

19. An irrigation closure according to claim 1 wherein the narrower section extends substantially from the edge to the centre of the membrane.

20. An irrigation closure according to claim 1 wherein the cross-section of the narrower section is less than one third of the cross-section of the wider section.

21. An irrigation closure according to claim 1 wherein the cross-sectional area of the wider section is at least one sixth of the total membrane surface area.

22. An irrigation closure according to claim 21 wherein the wider section has a cross-sectional area of at least one quarter of the total membrane surface area.

23. An irrigation closure according to claim 1 wherein the end of the wider section is provided with a pull-out aid.

24. Pouring closure according to claim 23, wherein the pull-out aid is formed as a pull ring.